The term “railroad track ears” is a common, non-medical phrase used to describe a specific congenital ear anomaly. This description refers to the appearance of a small pit or fold of skin near the front of the ear, which can sometimes look like a small track or line. While the physical appearance may cause concern, this condition is generally benign and present from birth.
Medical Identity of “Railroad Track Ears”
The correct medical term for what is commonly called “railroad track ears” is a Preauricular Sinus or Preauricular Pit. This condition is classified as a congenital malformation of the soft tissues located just in front of the external ear canal. The small opening typically appears near the anterior margin of the helix, which is the outer rim of the ear.
The “railroad track” nickname comes from the appearance of a small, linear depression or the double line created by an underdeveloped fold of the ear cartilage. This pit is the opening of a skin-lined tract that can vary in depth and length, sometimes branching out beneath the skin. The condition is relatively common, with prevalence ranging from 0.1% to 0.9% in the United States and up to 4% to 10% in some parts of Asia and Africa.
Preauricular sinuses are typically found on only one ear, though they can be present bilaterally. When the condition is bilateral, there is a higher likelihood that the trait was inherited. The presence of this small opening is usually the only symptom, and the pit itself does not affect a person’s hearing.
Embryological Origin of the Anomaly
This congenital anomaly occurs because of an irregularity during the development of the ear in the womb, specifically around the sixth week of gestation. The outer ear, or auricle, forms from the fusion of six small growths of tissue known as the hillocks of His. Three of these hillocks arise from the first branchial arch, and the other three arise from the second branchial arch.
The formation of a preauricular sinus is the result of the incomplete or defective fusion of these six hillocks. This failure to fuse completely leaves behind a small, skin-lined tract or opening in the skin.
Signs of Infection and Complications
For many people, the preauricular sinus remains asymptomatic, causing no problems throughout their lives. However, the pit is lined with skin cells and is a blind-ended tract, meaning it can collect dead skin cells and debris. This accumulation can lead to the tract becoming colonized by bacteria, resulting in a preauricular sinus infection.
An infection in the sinus tract is the most common reason people seek medical attention for this condition. Signs of an infection include localized pain and tenderness around the pit. The area will typically become visibly red and warm to the touch, often accompanied by noticeable swelling.
In some cases, the infection can progress to form an abscess, which is a painful collection of pus beneath the skin. Patients may also notice a foul-smelling discharge or fluid draining from the small pit opening. If an infection occurs, prompt medical evaluation is required, as it may necessitate a course of oral antibiotics to target the bacteria, which are most commonly Staphylococcus aureus or Staphylococcus epidermidis.
Treatment Options and Prognosis
When a preauricular sinus is present but never causes discomfort or infection, no medical treatment is required, and the pit is simply monitored. If the sinus becomes repeatedly infected or develops recurrent abscesses, surgical intervention becomes the recommended course of action.
The definitive treatment for recurrent infections is a procedure called surgical excision, or sinusectomy, performed by a specialist like an otolaryngologist. The goal of the surgery is to completely remove the entire sinus tract, including any branching portions, to prevent future infections. If an active infection is present, it is first treated with antibiotics and possibly drainage of any abscess before the definitive excision is performed.
The prognosis for individuals with a preauricular sinus is generally favorable. In rare instances, the presence of a preauricular sinus may be associated with other congenital anomalies, such as those related to the kidneys or hearing, which is why a medical evaluation is sometimes advised. For most people, the condition is an isolated finding, and surgical removal for recurrent infection is highly effective, with recurrence rates typically low when the entire tract is successfully removed.